WO 00/29249 discloses a vehicle seat, with a seat part and a seat back part held on the seat frame by side cheeks and movable relative to the frame by an actuating drive. The actuating drive has body position detectors control-connected for moving the respective seat part or seat back part forward or backward to the body position assumed by the seat occupant or according to the body movement of the seat occupant. In this known approach, the seat part and the seat back part are adjustably guided in a type of restricted guidance, and are pivotally connected to one another by an articulated axis. The seat part and the seat back part are each guided with a distance to the articulated axis and are rotatable around their guide axes. The indicated body position detector is designed as a distance measuring means, but can also be a pressure sensor or pressure switch which allows adjustment motion of the seat controlled by the operator.
The known seat design is ergonomically perfected and allows a plurality of adjustment possibilities. The seat part and seat back part can also be controlled and adjusted separately from one another. Based on the indicated sensor technology by the body position detectors, the associated control cost for the seat is correspondingly high so that the known seat design is expensive and complex to produce. As a result of the plurality of components and the indicated control, failures in operation cannot be avoided. Furthermore, the known seat is relatively heavy, indicating that its use in the aircraft domain is not altogether practical, so that the pertinent seats are used preferably in the first class section of aircraft.
U.S. Pat. No. 5,636,898 and EP-A-1 057 725 disclose comparable seat designs. The front area of the seat part is raised automatically with the tilt adjustment of the seat back into a backward position, by which the tilt adjustment for the seat part itself inevitably arises. Since the raising of the thigh of the seat occupant is associated with the raising of the front edge of the seat part, overall the legs are moved away from the respective floor of the vehicle. This movement is perceived as not always pleasant from the ergonomic standpoint of the operator or passenger.
Conversely, DE-C-42 22 222 and U.S. Pat. No. 5,133,587 have already proposed essentially fixing the front area of the seat part by a type of rotary or swivel function in height relative to the floor and swivelling the seat back together with the seat part. The seat back and seat part are designed as a common shell for a change in the position of the seat components relative to the front edge of the seat part. In the pertinent designs, generally a distinct tilt adjustment of the seat back, in addition to its lowering into the backward position, is necessary in order to be able to lower the seat part in an ergonomically favorable manner in the back area. For a correspondingly comfortable adjustment process, the seat back, therefore, has to be inclined far back. This arrangement entails loss of comfort for the individual in the row of seats behind.